As background art in this technical field, there is Japanese Patent Application Laid-Open No. 2010-8344 (Patent Literature 1). This publication contains the following description: “Opening information is acquired from the outside by the acquiring unit 103. When the opening information is acquired, in map data including usable roads and unopened roads stored in the storing unit 101, an unopened road corresponding to the opening information is changed to a usable road by the changing unit 104. A note of un-usability corresponding to the changed road may be changed to a note of usability.
Subsequently, predetermined processing such as map display processing for causing the display unit 102 to display a map including the usable roads, route search processing for searching for a route targeting the usable roads, and expressway-facility-information display processing for causing the display unit 102 to display information concerning usable expressway facilities is executed by the processing unit 105 using the usable roads without using the unopened roads.”